RE: move useProtectedContext calls to drawLayers

This change removes a race condition when calling RenderEngine from
multiple threads. Before this change, two competing threads could call
RenderEngine::useProtectedContext with different values, potentially
causing RenderEngine::drawLayers to use the wrong context.

We currently call RenderEngine from a single thread but that will change
with the upcoming refactor of SurfaceFlinger::renderScreenImpl.

Bug: 238643986
Test: presubmits
Change-Id: I78ca00797b1604cedae1f134e963b6b78f2b802f

1 files changed, 13 insertions, 0 deletions

diff --git a/libs/renderengine/RenderEngine.cpp b/libs/renderengine/RenderEngine.cpp
index 9d9cb6b2bc..f1fc0a45ad 100644
--- a/libs/renderengine/RenderEngine.cpp
+++ b/libs/renderengine/RenderEngine.cpp
@@ -19,6 +19,7 @@
 #include <cutils/properties.h>
 #include <log/log.h>
 #include "gl/GLESRenderEngine.h"
+#include "renderengine/ExternalTexture.h"
 #include "threaded/RenderEngineThreaded.h"
 
 #include "skia/SkiaGLRenderEngine.h"
@@ -70,10 +71,22 @@ ftl::Future<FenceResult> RenderEngine::drawLayers(const DisplaySettings& display
                                                   base::unique_fd&& bufferFence) {
     const auto resultPromise = std::make_shared<std::promise<FenceResult>>();
     std::future<FenceResult> resultFuture = resultPromise->get_future();
+    updateProtectedContext(layers, buffer);
     drawLayersInternal(std::move(resultPromise), display, layers, buffer, useFramebufferCache,
                        std::move(bufferFence));
     return resultFuture;
 }
 
+void RenderEngine::updateProtectedContext(const std::vector<LayerSettings>& layers,
+                                          const std::shared_ptr<ExternalTexture>& buffer) {
+    const bool needsProtectedContext =
+            (buffer && (buffer->getUsage() & GRALLOC_USAGE_PROTECTED)) ||
+            std::any_of(layers.begin(), layers.end(), [](const LayerSettings& layer) {
+                const std::shared_ptr<ExternalTexture>& buffer = layer.source.buffer.buffer;
+                return buffer && (buffer->getUsage() & GRALLOC_USAGE_PROTECTED);
+            });
+    useProtectedContext(needsProtectedContext);
+}
+
 } // namespace renderengine
 } // namespace android